I just switched over after being a long time Movable Type user, and here's a couple of newbie impressions that I have.
2 areas where I liked MT better were:
I like being able to browse through all my posts easily. As far as I can tell, in WP I can only see the last 15 and past that I have to browse by the month.
Second, I really would like to be able to click on a category in the management screen and see all the entries in that category. I kept seeing one entry in "uncategorized" and could not for the life of me figure out what it was since nothing showed up on my web page if I browsed that category. I eventually realized it was a Page I created. Doh!
I've been tempted to go back to MT since I know it and I haven't been able to replicate my old page exaclty (or the plugins I had), but I'm sticking with WP, because:
There are other things I like better about it
I will probably grow to like it even more over time
I like that it's open source and produces valid code!
I just "feel" better about it. 1.5 rocks! I'd tried earlier versions and they just couldn't pull me away form MT.